Charles r



(No Model.)

C. R. PRATT. GONTROLLING MBGHANISM.

Patented Sept. 8,1891.

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UNITED STATES CHARLES R. PRATT,

PATENT OFFICE.

oF NEW YORK, N. Y.

CONTROLLING MECHANISM.

SPECIFICATION forming part of Letters Patent No. 459,090, dated September 8, 1891.

Application filed October S0, 1890. Serial No. 369,816. (No model.)

To all whom, t may concern:

Be it known that I, CHARLES R. PRATT, a citizen of the United States, residing at New York, in the county and State of New York, have invented a certain new and useful Improvement in Mechanism for Controlling Electric and other Motors, of which the following is a specification.

This invention relates to means for starting, stopping, and reversing mot-ors or other mechanism; and the object of the invention is to provide simple means for the purpose named which shall be so constructed that it cannot be operated to reverse the motor or machine until the part which was moved to cause the motor to turnV in one direction shall be brought entirely back to the zero or normal position, and the construction is such that when operated to move the motor in one direction the means for moving the motor in the opposite direction will be locked; another object of the invention is to provide an improved controlling and safety device, as hereinafter described.

The invention consists in an apparatus the principles and construction of which are illustrated in the accompanying drawings, in which* Figure 1 shows the controlling mechanism applied to an elevator. Fig. 2 is a view at right angles to Fig. l, and Fig. 3 is a diagram of the circuit connections which may be employed.

1 indicates the elevator-can and 2 the hoisting-cable, which passes to the top of the elevator-shaft over suitable pulleys to the hoisting mechanism, which is not shown, since it does not forma part of the present invention. The hoisting mechanism preferred is operated by an electric motor, which can be driven in one direction to raise the elevator-car and in an opposite direction to lower it in a wellknown manner. Such a motor is indicated at 3 in Fig. 3.

At some suitable point, preferably at the bottom of the elevator-well, is placed means for controlling the elevator mechanism. The means shown is in two sections and consists of two circuit-closers 4. 4.. Each circuit closer or changer consists of a pulley 5, suitably journaled and having a switch-arm 6 provided with suitable contacts 7 for electrically connecting the circuitterxninals S and 9, respectively, supported on the switch-board l0. The switch-arms and contacts, with their supports, are termed controllers for the motor. Around these pulleys are placed cables 1l 11', one side of each cable passing' through the ear, as shown, the cables being provided with pulleys at the top of the elevator-well.

Rigidly connected with the pulleys 5 are projecting iianges 12, each of which is provided with a depression or notch 13. When the elevator-car is at rest and the motor is out of circuit, the two notches face each other and the wheel let on the pivoted standard l5 rests loosely between the two iianges and either of the pulleys and switch-arms'cau be moved. Then either of said pulleys is moved, (for example et, as shown in Fig. 1,) the wheel 14 is pressed toward the other pulley riding on the surface of the rim of the pulley first moved, thereby forming a lock for the other pulley.

1G are blocks which constit-ute stops for the circuit-closers. Preferably an elastic material 17 is connected with the block 1G to forni a cushion, against which the co-operating pro` jection 1S on the rim 12 may strike.

On the cable 11, preferably near the bottom of the elevator-well, is fixed a stop 19, having an elastic striking-surface 20.

Below the bottom of the car is a freely-suspended weight 2l, preferably arranged to slide over the shifting cable 11.

On the cable l1', preferably near the top of the elevator-well, is a freely-suspended weight 22, connected to the cable at 23.

24 is a weight fixed to the cable on the other side of the pulley and forming a counter-balance for the weight 22.

25 is an elastic striking-block on the top of the elevator-car. These cables and weights constitute means for operating the controllers.

Referring now to Fig. 3, the circuit connections will be described. From the plus side of a supplycircuit a branch wire leads through the held-magnet coil of the elevator-motor 3, thence to a contact J on the upper switeln board, and to a similar contact on the other board. lVhen the contacts 9 at the upper board are united by means of the switch-arm G and a contact 7, the circuit is continued by wire26 to the motor-armature,thence by wire ECO 27 to contact 8, thence to and through the re` sistances 28, and to the negative side of the supply-circuit. The circuits will be similar when the lower switch is operated, except that the circuit through the armature will be in the opposite direction.

The operation of Ythe above-described apparatus will now be briefly set forth. Suppose the elevator-car to be at the bottom of ro the Well and it is desired to ascend. The operator in the car will pull down cable l1', throwing arm 6 of circuit-closer 4 onto its contacts, thereby closing the circuit through the motor in the direction to raise the elevator-car. The cable is moved to a greater or less extent in accordance with the amount of resistance 28 which it is necessary to throw out of circuit in order to regulate the current to give the mot-or sufficient power to 2o do its work.

throw the motor out of circuit before the car reaches the top of the elevator-well, the car will strike the weight 22 and raise it, destroy- .ing the balance between 22 and 24, when 2 5 weight 24 will operate to turn the switch back to its Zero position, thus opening the motorcircuit. The length of the cord or wire Supporting Weight 22 is so adjusted as to stop the car at the proper point. When it is de- 3o sired to descend, 4 having been moved backto zero, the operator in the car will move cable 1l, closing the motor-circuit at the other circuit-closer, as will be evident from the dian gram. Should the operator fail to stop the motor before the car reaches the bottom of the well, the weight 2l will strike the stop 19 2O and move the switch-arm back to its Zero position, thus opening the motor-circuit and stopping the elevator-car at the proper point.

The advantage of operating the circuit-closers bymeans of the freely-suspended weights are obvious, the main advantages being the ease with which the position of the weights can be changed or adjusted and the gradual manner in which they operate on the cables which move the pulleys. As has already been indicated, it is necessary to return one pulley to its zero position before the other can be operated. This arrangement makes it certain 5o that the circuit through the motor in one direction will be entirely opened before the circuit is closed through the motor in the opposite direction. The stops 17 give the operator positive means for determining when 5 5 the switch-arms are brought to the zero position, since they can be moved no farther, and the operator is not obliged to depend on the use of his eye orhand to note the position of a device secured to the cable in the car.

6o When the weight strikes the stop on the cable,

it moves it to open the motor-circuit before the car or the elevator mechanism reaches the end of its travel, and the strain on the cable is only that due to the weight. This 6 5 strain is much less than in old arrangements, in which the car itself co-operates directly with a stop on the cable. In the latter case Should the operator fail tol when the car going at a high speed'st-rikes the stop it frequently breaks the cable, even when elastic buffers are used. This difiiculty is overcome by my arrangement of suspended weights, which are movable in relalation to the car, as will be evident. This apparatus would stop the car before it reached the end of its travel; but at the same time the operator can retain control 0f the car by pulling on the cable to overcome the effect of the weight.

It will be evident that the locking device is applicable to other forms of apparatus thanV those shown in the drawings. Hence l do not conne myself to the exact construction shown.

Having thus described the invention, what I claim isl, The combination of a motor having a suitable source of power for driving it, a lcontrolling device for the motor, made in two sec-4 tions, one for admitting said power to the motor in one direction and one for admitting power to the motor in the opposite direction, and a lock operated Vby the movement of either section to hold the other at its normal position, substantially as described.

2. The combination of a motor movable in two directions, a controlling device for ad mitting power to the motor to cause it to move in one direction fand a separate controlling device for admitting power to cause the motor to move in the opposite direction, means for moving either of said devices, and a lock operated by movement of the first controlling device to hold the other, said lock consisting of a pivoted lever between the two devices, and said lock being released when the first device is returned to zero, substantially as describedl v 3. The combination of an elect-ric motor having a suitable current-supply, a circuitchanger for admitting current to the motor in one direction and for regulating the current strength, a circuit-changer for admitting current to the motorin the oppositedirection and for regulating current strength, and a lock for'the circuit-changer, substantially as described.

4. A double circuit-changer consisting of two switch-arms with co-operating contacts, means for moving either section of the circuit-changer, and a lock operated by movement of either section to hold the other section, substantially as described.

5. A double circuit-changer consisting of two switch-arms, disks adapted to rotate, to which said arms are connected, co-operating contacts. for said arms, and a lock operated by the movement of either disk to lock the other, substantially as described.

6. A double circuit-changer consisting of two disks mounted side by side, switch-armsv movable with the disks, and a lock between the disks thrown into positive engagement by the movement of either disk, substantially as described.

IOO

'7. A double circuit-changer consisting of two disks mounted side by side, switch-arms movable with the disks, and a locking-wheel supported between the disks, substantially as described.

8. The combination oi' a motor, a device for controlling admission of power to the motor, and a freely-suspended weight moving with or in accordance with the apparatus driven by the motor and acting on said device to move it, substantially as described.

9. The combination of au elevator-car, a motor, a controlling device for controlling admission of power to the motor, a freely-suspended Weight, a cable connected to said device for moving' it, and a fixed stop on the cable, said freely-suspended weight being movable in line with the stop, substantially as described.

lO. The combination, with an elevator-car, of a motor, a controller for the motor, a cable connected to the control-ler, a fixed stop on the cable, and a weight suspended in position to strike said stop when the car is near the limit of its movement, substantially as described.

11. The combination, in an elevator apparatus, of a motor, a device for controlling admission of power to the motor, a cable connected to said device to move it, a weight by which the cable may be moved, said weight being normally restrained from action, and a second weight in the path of the elevator-car and adapted to be moved thereby for causing` said first-mentioned weight to act on the cable, substantially as described.

12. The combination, in an elevator apparatus, of a motor therefor, two devices for controlling admission of power to the motor, cables for operating said devices, one in one direction and one in the opposite direction,

CHAS. R. PRATT.

Witnesses:

BYRON TRAVER, CHARLES M. CATLIN. 

